Bind 9 truncating responses

Stephen Vickers stephen at n3k.co.uk
Fri Apr 22 07:42:45 UTC 2005


Can anybody comment?
 

First things first: I understand that 50 NS records in a zone are not good
practice however situations require that this be the case.

 

I have been completing some testing where I have approx 50 NS records within
a zone.  When I place this zone on a Bind 9 Server and query for an A record
in this zone from nslookup Bind places the answer in the answer section
correctly.  It then jams as many NS and Glue records in the additional and
authority section as possible.  As not all of the NS and Glue records fitted
in the packet the Bind 9 Server sets the TC bit in the DNS header.  This
same test on Bind 8 shows different behaviour as Bind 8 does not set the TC
bit.

 

Should Bind 9 be doing this as it supplied the answer?  Setting the TC would
cause most implementations to retry the query via TCP causing more work for
the Server and using up a TCP resource.

 

Are the NS and A records considered required/important for the response to
an A record query?

 

Cheers

 

---------- 
 
Stephen Vickers 
 
Technical Support
n3k Informatik Limited 
The Square 
Basing View 
Basingstoke 
RG21 4EB 
 
Email:               support at n3k.co.uk
Tel:                  012 5630 3700 
Fax:                  012 5630 3701 
Support:            012 5630 3777 
Web:                www.n3k.co.uk 
 
Important Notice 
 
The information contained in or attached to this email is intended only for
the use of the correct addressee(s). If you are not the intended recipient,
or a person responsible for delivering it to the intended recipient, you are
not authorised to and must not disclose, copy, distribute, or retain this
message or any part of it. It may contain information which is confidential
and/or covered by legal professional or other privilege (or other rules or
laws with similar effect in jurisdictions outside England and Wales).
 
The views expressed in this email are those of the author and not
necessarily the views of the company, its directors, officers or employees
and we make no representation or accept any liability for its accuracy or
completeness unless expressly stated to the contrary.
The company will not be liable for direct, special, indirect or
consequential damages arising from alteration of the contents of this
message by a third party or as a result of any virus being passed on. The
company has implemented virus detection systems to minimise the risk of
passing on viruses.
The company records all e-mail messages sent to and from this address and
reserves the right to monitor and examine content for the purposes of
training, quality control and for investigating or detecting any
unauthorised use of its system and for ensuring its effective operation.

 






More information about the bind-users mailing list